C++ for Scientists - Technische Universität Dresden

200 CHAPTER 7. EFFECTIVE PROGRAMMING: THE POLYMORPHIC WAY
far already deal with some kind of code reusability, but mostly in an implicit way. The following
section overview polymorphic mechanisms in a more explicit way.
As soon as code reusability is covered, an almost equal importance is placed on code extensibility,
which should not be constrained by reused code. Scientific code development is always
driven by transforming newly developed scientific methods into executable code. Various programming
techniques with different scopes are therefore mandatory. If programming techniques
are analyzed this way, it becomes understandable why some of the presented programming
paradigms are not ideally suited to accomplish code reusability and extensibility together (e.g.,
the object-oriented inheritance model).
No technique, or more generally paradigm, will result in the ultimate and final solution, but
each of the techniques results in tools to manage the complexity of a problem. It does not give
you the ability to do so. A bad problem specification will lead to a bad solution independently
from the technique or paradigm used for implementation.
The usage of the Boost graph library (BGL) is an excellent example. There is great diversity
of requirements in the field of graph algorithms and data structures. Even so, the performance
claim for a library like this, is very high. Nevertheless, it was possible to implement all necessary
functionality at a high performance level. More than this, the library can be extended greatly
in many different ways. But on the other side, this library is not easy to use or extend without
an understanding of the underlying techniques.
And as a reminder of the main goal of this book is how to write good scientific software.